Removed white space on sides but not on top and bottom

I’m trying to make my header image take up the whole header space. I’ve been able to get rid of the white space on the sides, but not on the top and bottom. I’ve checked out the mouseclick tutorial and copied the code into my custom css field, but I still can’t seem to remove the padding from the top and the bottom. Any help would be much appreciated!

Here’s a link to my site: http://fstpetcare.com